题解 | #字符个数统计#

const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;

void async function () {
    // Write your code here
    let line = await readline()
    let tokens = line.split('');
    let a = [...new Set(tokens)]
    // let tokens = line.split('');
    // let newObj = {}
    // tokens.forEach((item) => {
    //     if (!newObj[item]) {
    //         newObj[item] = item
    //     }
    // })
    // let a = []
    // for (let key in newObj) {
    //     a.push(key)
    // }
    console.log(a.length);
}()